>>1686238Your own towels, your own pillow, your personal medicine chest (stomach meds, seasickness pills, ibuprofen), a shower curtain+rings (you would not believe how often you get to your cabin to find it doesn't have a fucking shower curtain for some reason), and a foldable laundry basket/hamper. Also, you know the amount of underwear and socks you're bringing? Double it.
Also, bring some ear buds or headphones for your phone, and load it up with music. Alternatively, if you have the money, get a Walkman mp3 player. When you're working on-deck, the ability to use put music on and drift away while you work is invaluable. And if you aren't working on deck, it'll prove useful when working out in the gym.